We look at the division of 21851307 by 10 
We want to figure out the number of times 21851307 can be divided by 10.

Going ahead to step 1:
2 divided by 10 is 0 with a remainder of 2.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 2, we end up with 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 10

On to step 2:
21 divided by 10 is 2 with a remainder of 1.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Subtract 20 from 21 to get 1.
Bring next digit (8) of the dividend behind the 1 and repeat the process: 18 / 10

Moving on to step 3:
The number 10 fits into 18 1 times, leaving a remainder of 8.
The next digit of our result is 1. 
Result so far: 21.0
If we take 10 away from 18, we end up with 8.
Bring next digit (5) of the dividend behind the 8 and repeat the process: 85 / 10

Moving on to step 4:
When dividing 85 by 10, we get 8 with a remainder of 5.
The next digit of our result is 8. 
Result so far: 218.0
The remainder is 5 after subtracting 80 from 85.
Take the next digit (1) from the dividend and append it to 5, then repeat: 51 / 10

Advancing to step 5:
When dividing 51 by 10, we get 5 with a remainder of 1.
The number 5 becomes the next digit in our result. 
Result so far: 2185.0
If we subtract 50 from 51, we get 1.
Bring next digit (3) of the dividend behind the 1 and repeat the process: 13 / 10

Going ahead to step 6:
10 can be fit into 13 1 times, resulting in a remainder of 3.
Use 1 as the next digit of our solution. 
Result so far: 21851.0
If we take 10 away from 13, we end up with 3.
Fetch the next digit (0) from the dividend, attach it to 3 and continue: 30 / 10

On to step 7:
When dividing 30 by 10, we get 3 with a remainder of 0.
The next digit of our result is 3. 
Result so far: 218513.0
Subtracting 30 from 30 leaves us with 0.
Take the next digit (7) from the dividend and append it to 0, then repeat: 7 / 10

Step 8:
The number 10 fits into 7 0 times, leaving a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 2185130.0
The remainder is 7 after subtracting 0 from 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

On to step 9:
The number 10 fits into 70 7 times, leaving a remainder of 0.
The number 7 becomes the next digit in our result. 
Result so far: 2185130.7
Subtracting 70 from 70 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 10:
The number 10 fits into 0 0 times, leaving a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 2185130.7
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 11:
The number 10 fits into 0 0 times, leaving a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 2185130.7
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 2185130.7, with a leftover of 0.0.